Electrophoresis of tears, a rapid and easy technique, shows several peaks of migration. Three main peaks correspond to the proteins synthesized by the lacrimal gland: rapid migrant proteins, lactoferrin migrating to the anode, and lysozyme migrating to the cathode. Secretory tissue injuries of the lacrimal gland show a more or less important decrease of one or several peaks. Any inflammatory reaction induces an increase in the serum albumin and immunoglobulin fractions. This exploration can be helpful in the diagnosis of the sicca syndrome or of drug poisoning thereby avoiding lacrimal biopsy.